1. Technical Field
This invention relates generally to multicolor document copiers, and more specifically to the provision of a color palette from which colors can be operator selected.
2. Background Art
U.S. Pat. No. 4,045,218 discloses an electrophotographic copier adapted to produce reproductions from single color originals such that selected portions of the image are reproduced in a second color toner contained in a second development station. U.S. Pat. No. 4,791,450 teaches an improvement wherein color selection may be made from a menu of many different colors, say for example 25 different colors, without providing significantly more color development stations. This is of course effected in a color copier using subtractive colored toners of cyan, magenta, yellow, and black in various combinations to produce different colors.
In copiers adapted to produce only a very few colors, the accuracy of the color reproduction is not considered to be very critical. An operator who wants part of the image to stand out from the rest probably does not care what shade of red, blue, or other color is used. Color selection may be made from a short word list of colors, or from a color image of those few colors available. If the latter, experience shows that operators are not disappointed if the reproduced color does not closely match the illustrated color.
On the other hand, when many colors are offered, it becomes difficult if not impossible to describe the colors by words. Therefore, color palettes have been employed to show an operator the color options available. But this practice presents a problem. When there are many closely related colors available, operators tend to be more critical of differences between the reproduced color and the color selected from the palette.
Differences between the color shown on the palette and the actual color produced may result from differences between the color ink used to produce the palette and the color toner or ink used to make the copy. Further, the actual color produced can vary from time to time due to photoconductor fatigue, changes in machine environment (temperature and relative humidity), improper adjustment, etc. Accordingly, any palette which correctly represented colors under one set of conditions would not necessarily be correct under another set of conditions.